Advances in the field of wireless LAN technology has led to the availability of relatively inexpensive wireless LAN equipment, which, in turn, has resulted in the emergence of publicly accessible wireless LANs (e.g., “hot spots”) at rest stops, cafes, libraries and similar public facilities. Presently, wireless LANs offer users the opportunity to access a private data network, such as a Corporate Intranet, or a public data network such as the Internet. Few if any publicly accessible wireless LANs offer any type of telephone service, let alone, wireless telephony service.
Presently, users desirous of obtaining wireless telephony service typically subscribe to one of many providers of such service. Today's wireless telephony service providers not only offer voice-calling capability, but also offer General Packet Radio Service (GPRS), thereby affording subscribers the capability of exchanging data packets via a mobile terminal. While GPRS exists in many areas, data transmission rates typically do not exceed 56 Kbs and the costs incurred by wireless network service providers to support this service remain high, making GPRS expensive.
The relatively low cost to implement and operate a wireless LAN, as well as the available high bandwidth (usually in excess of 10 Megabits/second) makes the wireless LAN an ideal access mechanism through which a mobile terminal user can exchange packets with a wireless telephony network. Indeed many wireless LAN networks offer users a much higher Quality of Service (QoS) level in comparison to the QoS level offered in connection with GPRS. Indeed, even the proposed “Universal Mobile Telecommunications System 3GPP” standard for advanced packet radio service through wireless telephony networks, as is well known in the art, will not afford a QoS level as high as present-day wireless LAN networks.
Most mobile terminal users that access the wireless telephony network through a wireless LAN expect to obtain the higher QoS level available through the wireless LAN. Unfortunately, no mechanism currently exists that allows a mobile terminal user to easily transition between a wireless telephony network and a wireless LAN while affording the user the ability to obtain the higher QoS level in the wireless LAN network. Presently, a mobile terminal initially obtains service from a wireless telephony network by attaching itself to the network via a Packet Data Protocol (PDP) context. To establish a PDP context, the mobile terminal user makes a PDP context request in which the mobile user identifies itself to the wireless telephony network. In the PDP context request, the mobile terminal user typically specifies a QoS level that is available in the wireless telephony network. In response to the PDP context request, the wireless telephony network assigns an Internet Protocol (IP) address to the mobile terminal user to enable the exchange of data packet. In addition, the wireless network will reserve the resources needed to provide the mobile terminal user with the specified QoS level.
To obtain the higher QoS level available through the wireless LAN, a mobile terminal user could establish a separate PDP context within the wireless LAN. To establish such a PDP context, the mobile terminal user would make a PDP context request specifying a QoS level available in the wireless LAN. After establishing the PDP context within the wireless LAN, the mobile terminal user will receive a new IP address different from the address assigned during with the PDP context established with the wireless telephony network. When the mobile terminal user transitions from the wireless LAN back to the wireless telephony network, the mobile terminal user will need to establish a new PDP context. In practice, the wireless telephony network will not accept the PDP context associated with the wireless LAN. The need for a mobile terminal user to establish a new PDP context upon transitioning from the wireless LAN to the wireless telephony network consumes unnecessary resources.
Thus, there is need for a technique that enables a mobile terminal user to seamlessly transition between the wireless network and the wireless LAN while enabling the mobile terminal user to enjoy the higher QoS level available in the wireless LAN.